Study On Antifungal Effect Of Wood Tar

Wood tar is a substance derived from the wood by high temperature distillation.The main ingredients of it are phenolics(phenol,guaiacol,O-phenol etc).Early in the medical,Wood tar has been used for treatment a variety of skin diseases(such as ulcers,pus,rot,etc.).In recent years,some scholars have reported Wood tar(bamboo tar)has antifungal activity on the part of the fungi.Therefore,Wood tar has the development of plant-source fungicide target.In view of this,the main contents of this paper include:screening wood tar antifungal spectrum;researching wood tar soluble liquid and liniment;performing systematic activity determination.The main results can be briefly described as follows:1,The antifungal activity was determined with mycelium growth rate method.The results showed it had different inhibition against 19 plant pathogenic fungi,especially against Valsa mali;At the 0.25 mg/mL concentration of Wood tar the inhibition rate of V.mali were 86.02%,and the EC50 was 0.07811 mg/mL.At the 0.5 mg/mL concentration,the inhibition rate of Botrytis cirerea and Thanatephorus cucumeris were 88.12%and 81.41%respectively;but at the 0.5 mg/mL concentration,the inhibition rates against Botryosphaeria dothidea and Curvularia lunata pathogen were less than 50%.It aslo showed that Wood tar has a relatively wide range of inhibitory activity,especially of V.mali.The antifungal activity of Wood tar need for further systematic research.2,The formulation of 15%Wood tar SL was developed.The ingredients of 15%Wood tar were as follows:15%Wood tar,10%ethanol,10%cosolvent A,10%1-methyl-2-pyrrole,15%emulsifier A,40%water.3,The formulation of 15%,30%,50%Wood tar liniment was developed.The following ingredients of 10%emulsifier A,5%JFC were the same in three different concentrations of Wod tar liniment.The difference was that 15%wood tar liniment contented 2%bentonite,2%xanthan gum,68%water;30%wood tar liniment contented 1.5%bentonite,1.5%xanthan gum 53%water and 50%wood tar liniment contented 1%bentonite,2%xanthan gum,33%water.4,The control effects in vivo of 15%Wood tar SL was determined by pot tests and tissue tests against B.cirerea and Blumeria graminis.The results can be drawn:when 15%Wood tar SL was diluted 100-fold,the protective and therapeutic effects were 44.38%and 35.42%on B.cirerea,and when 15%Wood tar SL was diluted 200-fold,the protective and therapeutic effects were 41.91%and 55.86%on B.graminis.Clearly,15%Wood tar SL has some control effects,but the efficacies were less than 50%Procymidone WP 1000-fold and 15%Triadimefon WP 1000-fold respectively.5,The control effects in vivo of Wood tar liniment was determined by tissue tests against V.mali.The results showed:at the concentration of 30%,50%and 100%Wood tar liniment,the protective and therapeutic effects were 100%and 99.38%on V.mali;at the concentration of 15%Wood tar liniment,the protective and therapeutic effects were 98.58%and 91.64%.At each concentration,they showed higher effect compared with the 10%Thiram paste.6,When 15%Wood tar SL was diluted 200-fold and 500-fold,the results of field efficacy trials showed that it had certain control effects on B.cirerea,but compared with the 2%Propamidine AS 1000-fold efficacy,the effect was not significant.7,The control effect of field efficacy trials was determined with different concentrations of wood tar liniment against V.mali.The results showed:at the concentration of 30%,50%and 100%Wood tar liniment,three drug effects were more than 75.0%.The effects were higher compared with the 10%Thiram paste.In summary,Wood tar has a good antifungal effect to V.mali,It has good prospects for promoting and applying in agriculter,and is worthy of further study.